diff --git a/src/common/richtooltipcmn.cpp b/src/common/richtooltipcmn.cpp
index c4671f63f1..4231ea8c7e 100644
--- a/src/common/richtooltipcmn.cpp
+++ b/src/common/richtooltipcmn.cpp
@@ -73,7 +73,7 @@ void wxRichToolTip::SetTitleFont(const wxFont& font)
     m_impl->SetTitleFont(font);
 }
 
-void wxRichToolTip::ShowFor(wxWindow* win, wxRect* rect = NULL);
+void wxRichToolTip::ShowFor(wxWindow* win, wxRect* rect)
 {
     wxCHECK_RET( win, wxS("Must have a valid window") );
 
diff --git a/src/generic/richtooltipg.cpp b/src/generic/richtooltipg.cpp
index 282f27e7a9..82f8b16966 100644
--- a/src/generic/richtooltipg.cpp
+++ b/src/generic/richtooltipg.cpp
@@ -673,7 +673,7 @@ void wxRichToolTipGenericImpl::SetTitleFont(const wxFont& font)
     m_titleFont = font;
 }
 
-void wxRichToolTipGenericImpl::ShowFor(wxWindow* win, wxRect* rect = NULL);
+void wxRichToolTipGenericImpl::ShowFor(wxWindow* win, wxRect* rect)
 {
     // Set the focus to the window the tooltip refers to to make it look active.
     win->SetFocus();